Objective To evaluate the effects of metformin on transforming growth factor-betal (TGF-β 1)-induced epithelial-mesenchymal transition (EMT) in and invasion of the human melanoma cell line 1205Lu.Methods In vitro cultured 1205Lu cells were divided into 3 groups to be treated with serumfree culture medium (blank control group),serum-free culture medium containing 5 ng/ml TGF-β 1 (TGF-β 1 group) and serum-free culture medium containing 5 ng/ml TGF-β 1 and 1 mmol/L metformin (TGF-β1 + metformin group),respectively.After 48-hour treatment,morphological changes of 1205Lu cells in the above groups were observed by using a microscope,and photos were taken at the same time.Transwell invasion assay was performed to estimate cellular invasive activity,Western blot analysis and real-time fluorescence-based quantitative RT-PCR were conducted to determine the mRNA and protein expression of N-cadherin and matrix metalloproteinase-9 (MMP-9),respectively.Statistical analysis was carried out by one-way analysis of variance (ANOVA) and least significant difference (LSD) test.Results Compared with the blank control group,the stimulation of TGF-β 1 could induce the epithelial-mesenchymal transition (EMT)-like morphological changes in 1205Lu cells,while TGF-β 1 combined with metformin could reverse the EMT-like morpho-logical changes.The number of 1205Lu cells crossing the transwell Matrigel per high-power field (× 200) was significantly higher in the TGF-β1 group (412.2 ± 13.427) than in the blank control group (194.1 ± 8.295) and TGF-β1 + metformin group (175.3 ± 8.693).Compared with the blank control group and TGF-β1 + metformin group,the TGF-β1 group also showed significantly increased mRNA and protein expression of N-cadherin (mRNA:6.678 ± 0.043 vs.1.000 ± 0.000,1.035 ± 0.015;protein:1.963 ± 0.016 vs.0.603 ± 0.029,0.207 ± 0.009) and MMP-9 (mRNA:5.351 ± 0.604 vs.1.000 ± 0.000,0.930 ±0.130;protein:1.243 ± 0.027 vs.0.575 ± 0.009,0.629 ± 0.008).Conclusion Metformin can obviously inhibit TGF-β1-induced EMT-like morphological changes in,the capacity to penetrate Matrigel-coated transwell chambers of and the mRNA and protein expression of N-cadherin and MMP-9 in 1205Lu cells.

BACKGROUND:There are many postmenopausal women taking hormone, which leads to much loss of bone mass, further inducing fragility fractures. The studies on the hormone exposure combined with ovariectomy-induced osteoporotic model are still immature, and the related molecular mechanism remains unclear. OBJECTIVE: To establish the rat osteoporotic model induced by ovariectomy combined with glucocorticoid exposure and to explore the underlying molecular mechanism. METHODS: Thirty 3-month-old female Sprague-Dawley rats were randomly divided into blank control, sham and model groups (n=10 per group). The rats in the blank control group received no intervention; rats in the sham group were clipped off a little of coeliac adipose tissue; the model rats received bilateral ovariectomy and 4-week administration of glucocorticoid. RESULTS AND CONCLUSION:At 4 weeks after modeling, compared with blank control and sham groups, the model group showed significantly lower bone mineral density of the femur, number of bone trabeculae and bone volume/total volume, and significantly wider bone trabecular spacing. Additionally, the model group revealed the damaged bone trabecular structure and thiner cortical bone. The expression level of Runx2 was downregulated whereas both collagen type 1α1 and peroxisome proliferators activated receptor γ mRNA were upregulated in the model group. These findings suggest that ovariectomized rats exposed to glucocorticoid rapidly develop femur osteoporosis, maybe by downregulating the expression of Runx2, as well as upregualting collagen type 1α1 and peroxisome proliferators activatedreceptor γ mRNA.